"A Letter to a Friend stands out among Nāgārjuna's works because of its minimal philosophical content and limited discussion of Mahayana practices. A Letter to a Friend is a comprehensive yet brief summary of the basic ideas and practices that form the substrate for all forms Buddhism: in other words, the text outlines the practices common to the Hinayana-more respectfully called the Śrāvakayāna-and the Mahayana in both its Sutrayana and Vajrayana forms. In that regard, it can be seen as a very early precursor of the presentation of the graduated path to awakening in a single text developed centuries later by Atiśa (circa 982-1055), and expanded in Tibet by the master Je Tsongkhapa (1357-1419). Geshe Sopa was an exemplary Buddhist monk practitioner as well as a superlative scholar. His quiet and compassionate traditionalism drew people in; he did not blast people with charisma. He was a recognized master of his tradition and also knew how to reach a contemporary audience. His teachings on A Letter to a Friend roughly follow the commentary written by Rendawa Shonu Lodro (1349-1412). However, he added much, much more. He brought in additional material from many sources: the sutras, other texts by Nāgārjuna, works by great Indian masters such as Śāntideva, Āryadeva, Candrakīrti, Vasubhandu and others, and from multiple works by Je Tsongkhapa.15 Although Nāgārjuna's text primarily teaches the common path with little emphasis on philosophy, Geshe Sopa's explanation supplements it to teach the Mahayana path and Madhyamaka philosophy"--